Photographic production of electrically conducting silver images



3,033,765 PHOTOGRAPHIC PRODUCTION F ELECTRE- CALLY CONDUCTING SILVER IMAGES James R. King and Grant M. Haist, Rochester, N.Y.,

assignors to Eastman Kodak Company, Rochester,

N.Y., a corporation of New Jersey N0 Drawing. Fiied June 6,1958, Ser. No. 740,136

21 Claims. (Cl. 204-15) This invention concerns the production of electrically conducting silver images, more particularly conducting images which may be used for obtaining printed circuits or for use in an electrostatic photographic process for reproducing prints.

Normal chemical development of the typical silver \halide photographic emulsion produces developed silver images that have almost no electrical conductance. For certain purposes, it has been desirable to have silver images produced photographically which could be used to conduct electricity. For instance, such imagesmight be used as a basis for printed circuits on which copper could be plated-or that may be used to produce multiple reproductions on ordinary paper stock by. a corona discharge method. We have discovered that electrically conducting silver images corresponding to the undeveloped portions of the print are formed by immersing a photographic paper in a monobath and transferring to 'a suitably prepared support.

One object of this invention is to obtain electrically conducting silver images. Another object is to obtain conducting silver images using a monobath treatment. A further object is to obtain electrically conducting silver images photographically which can be transferred onto film base.

The above objects are carried out by adding to the developer certain silver halide complexing agents so that the exposed photographic print .is developed in a single solution. We have found that a monobath comprising a silver halide reducing agent, an alkali, and B,B-dithiasuberic acid can be used to take the place of conventional processing involving three steps, development, fixation, and washing. An exposed photographic print is immersed from 30 to 90 seconds in a single processing bath then blotted to remove surface solution.

The processed image of the print is then transferred to a suitable receiving material, such as asubbedfilm support, which contains a nucleating agent. The support is nucleated by bathing in a bath containing a nucleating agent and then blotting and drying. A typical bath comprises for example a 1% gold chloride solution or alternatively a 1% .stannous chloride solution. In some cases better results are obtained by treating suc cessively in the two baths. In our preferred embodiment,

both baths are used. A print of the material to be transferred is immersed in a monobath for v3090 seconds and placed with the emulsion side down on the treated film support without blotting. A roller or a squeegee is brought to bear on the back side of the print and the excess process solution removed. After 604.00 seconds the film is stripped from the film support and the support allowed to dry. The image transferred to the support will conduct an electric current.

The following represents our preferred developing bath:

'Hydroxylarnine hydrochloride 5 to 3 0 g. per liter.

sufiicientquantity to control fog. Temperature 1030 65? C.

States Patent 0 "ice ,eral formula RCH SCI-I COOH in which B may be selected from the class consisting of CH ,CO OH and CH SCH COOH. These include (ethyl mercapto) acetic acid, thiodiglycolic acid, and ,B,B'.-dithiasuberic acid.

In some instances, an electrically conducting imagei's formed on the processed photographic paper itself provided a nucleating agent is present. For instance, such a silver layer is obtained following processing in the monobath with photographic papers having straight silver chloride emulsions.

With photographic papers having a silverbromidecontent, treatment with a nucleating afterbath permits formation of an electrically conducting layer on the paper itself without requiring transfer. Such an afterbath consists of such nucleating agents as soluble noble metal compounds such as gold chloride, tin compounds such as stannous chloride and the like. intact the .same nucleating baths used to prepare the nucleating support for transfer may be used, and the paper is immersed in the nucleating bath following removal from the monobath, blotted and dried.

Papers which normally give conducting silverimages, after immersion in the monobath, when .given a short treatment in thenucleating afterbath, will produce better silver conducting images in a shorter time than previously possible.

The following. examples .illustrate our invention but: are not intended to limit it in any way. Example .1..A solutionwas prepared asfollows:

Hydroxylamine hydrochloride g. perliter-.. 10.0 Sodium hydroxide do' 25 .0 fi,fl-dithiasuberic acid do 30.0 S-methyl benzotriazole V do 0.3 pH 12.6

An exposed photographic print on a straight silver chloride emulsion coated photographic paper was immersed for 30 seconds in this processing bath. A developed image of high contrast was obtained with the normally undeveloped .areas having a continuouswsilver white coating which appeared on drying. This coating conducted an electrical current when .measured with a Weston .Model 785 Circuit Tester withthe print 1probes .placed one centimeter apart.

Additional experiments with different photographic papers carrying straight silver chloride .emu'lsionsspro- .duced electrically conductingsilverlayers.

Example 2.-A solution having the following formula was prepared:

Hydroxylamine hydrochloride g. per 'liter 10.0 Sodium hydroxide 'do 25:0 Thiodiglycolic acid do 30. 0 S-methyl benzotriazole do .03 pH 12.6

image can, .if desired, be formed instead on areceiving support e.g., an all cellulose acetate film which had been nucleated .by bathing in a onepercent gold. chloride solution or the like, blotted anddried, and then similarly bathed in a onepercent stannous chloridesolution, blotted and dried. The print,.following processinginrthemonobath, was contacted face side down on the subbedfilm supportand the back of the print pressed using a;roller.

After 90 seconds, the print was stripped from the film and the support allowed to dry. The transferred image conducted electric current when measured as in Example l.

Example 3.--A monobath solution was prepared as described in Example 1 except that (ethyl rnercapto) acetic acid was used in place of fl,fi'-dithiasuberic acid. After processing the exposed print in the monobath it was then given a rapid dip in a solution containing 1 gram per liter of a gold salt. Silver images of good conductance were obtained with samples on photographic paper having emulsions containing silver bromide as well as silver chloride. Use of a silver salt or of a palladium salt instead of the gold salt produced similar results. The images obtained were transferred to film support as described in Example 2a with similar results.

Example 4.A monobath solution was prepared as described in Example 1. Prints using a photographic paper carrying an emulsion were processed in this monobath to produce smooth silvered non-image areas. Where the print was attached directly to a Multilith press, a reproduction of black letters on a speckled gray background was obtained with the ink having adhered to the electrically conducting layer.

Example 4a.A monobath having the following composition was prepared:

Phenidone (l-phenyl-S-pyrazolidone grarns 2.0 .Hydroquinone do 10.0 'fl,fi'-Dithiasuberic acid do 40.0 Sodium sulfite, desiccated do 100.0 Sodium hydroxide do 25.0 S-methyl benzotriazole do 0.5 Water to make 1.0 liter.

i The useful pH range of this formula is from 11.0 upwards.

. An exposed sheet of photographic paper carrying a silver chloride emulsion was immersed for 30 to 60 seconds in the above process bath to produce a print having separate silver white areas which are electrically conducting. The non-developed image areas can be transferred toa suitable nucleated support as described in Example 2a.

Example 5.-Conducting silver images in the form of electrical printed circuits obtained as described in Exam- -ples 1, 2 and 2a were plated using a water solution of copper sulfate and sulfuric acid and a 1%. volt dry cell battery. It was possible to solder wire directly to the copper plated surface andjhe circuits showed good electrical conductance.

Example 6.-A subbed film support was bathed in a 1% gold chloride solution, blotted and dried. The support was then treated with a 1% stannous chloride bath in the same manner, blotted and dried. An exposed photographic print on photographic paper containing in the emulsion a mixture of both silver chloride and silver bromide was processed in the hydroxylamine hydrochloride-5,}9-dithiasuberic acid solution monobath for 30 seconds and placed emulsion side down on the treated subbed iilm support Without blotting. A roller was brought to bear on the back side of the print and. the excess processing solution removed. After 90 seconds, the print was stripped from the film support and the support allowed to The images transferred to the support conducted an electric current. Conducting images were made from other photographic materials including papers having straight silver chloride emulsions, a film having a mixed silver chloride-silver bromide emulsion, and papers having mixed silver-chloride-silver bromide emulsions.

multiple reproductions on ordinary paper stoclc by an electrostatic printing method. In this procedure a negative charge was placed on the material to be reproduced.

Positively charged particles were then dusted on the surface with no adhesion to the conducting silver areas. A sheet of paper was placed over the dusted surface and then negatively charged, causing the positive particles to adhere to the surface of the paper. The paper was then baked to cause the particles to adhere to the paper base. This process Was repeated several times using the same silver transfer.

Use of electrically conducting silver layers may be made in various applications such as (1) a flexible printed circuit, (2) electrostatic printing processing (3) interdigital electrodes for cadmium sulfide photocells, (4) electrical card selection in the Minicard or IBM systems, (5) electrically-conductive strain gauges and humidity gauges, (6) metallic fibers for cloth, (7) silver coating on plastics or other materials, (3) replicas for electron microscopy, (9) electrotypes, (l0) condensers, (ll) conducting backing layers for photographic film, (12) planar dye transfer and (13) diffusion transfer processes.

As used herein, the term, photographic print, is intended to describe a light sensitive photographic emulsion on a paper base. It may be exposed to light or may have been processed so that it is a silver image on a paper base.

The time of immersion in the monobath is not critical but merely consists of a short period of immersion sufficiently long for the black silver image to be formed in the areas where this type of image is formed.

Other methods of applying the monobath solution or nucleating solutions may also be used such as a dip roll, hopper, spray and the like so that a sufficient amount of solution is applied to the surface.

The nucleating baths are operative at concentrations as low as 0.5% and as high as 5.0% and the time of immersion may vary. Proportions may be varied in the monobath using Phenidone and hydroquinone as follows:

Phenidone l -phenyl-3- In the operation of our invention all types of silver halide emulsion coated paper are operative when immersed in the monobath and contacted against a nucleated layer on a suitable support.

We claim:

1. A monobath composition comprising a siliver halide developer selected from the class consisting of 5-30 g. per liter hydroxylamine hydrochloride and a mixture of 0.5-5 g. per liter of l-phenyl-3-pyrazolidone, and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and fi,,B'-dithiasuberic acid.

2. A monobath composition comprising 5-30 g. per liter hydroxylamine hydrochloride and 5-100 g. er liter of a silver complexing agent selected from the c ass consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and 3,p'-dithiasuberic acid.

3. A monobath composition comprising 5-30 g. per liter hydroxylamine hydrochloride and 5-100 g. per liter of B,fi-dithiasuberic acid.

0 4. A monobath composition comprising 5-30 g. per liter hydroxylamine hydrochloride and 5-100 g. per liter of thiodiglycolic acid.

5. A monobath composition compriisng 5-30 g. per liter hydroxylamine hydrochloride and 5100 g. per liter of (ethylmercapto) acetic acid.

6. .A monobath composition comprising a mixture of 0.5-5 g. per liter of 1-phenyl-3-pyrazolidone, 530 g. per

complexing agent selected from the class consisting of (ethylmercapto) acetic acizl, thiodiglycolic acid, and

..B,B-dithiasuberic acid.

7. A monobath composition comprising a mixture of 0.5- g. per liter of 1-pheny1-3-pyrazolidone, 5-30 g. per liter hydroquinone and 5-100 g. per liter of B,B-dithiasuberic acid.

8. A monobath composition comprising a mixture of 0.5-5 g. per liter of 1-phenyl-3-pyralozidone and 5-30 g. per liter hyd-roquinone and 5-100 g. per liter of thiodiglycolic acid.

9. A monobath composition comprisinga mixture of 0.5-5 g. per liter of 1-phenyl-3-pyrazolidone, 5-30 g. per liter hydroquinone and 5-100 g. per liter of (ethylmercapto) acetic acid.

10. A process for the production of an electrically conducting silver image comprising immersing an exposed silver chloride photographic emulsion on a support for 1 30-90 seconds in a monobath comprising a silver halide developer selected from the class consisting of 5-30 g. per liter hydroxylamine hydrochloride and a mixture of 0.5-5 g. per liter of 1-phenyl-3-pyrazolidone, and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and B,B-dithiasuberic acid.

11. A process for the production of an electrically conducting silver image comprising immersing an exposed silver halide photographic emulsion on a support for 30- 90 seconds in a monobath comprising a silver halide developer selected from the class consisting of 5-30 g. per liter hydroxylamine hydrochloride and a mixture of 0.5 -5 g. per liter of 1-phenyl-3-py-razolidone, and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and [LE-dithiasuberic acid, transferring the conducting silver image to a subbed support which has been nucleated by bathing in a solution of a salt chosen from the class consisting of gold salts and stannous salts, blotted and dried, the transfer being effected by placing the support emulsion side down on the subbed support immediately following removal from the monobath and applying pressure to the reverse side of the support, stripping the emulsion from the support and permitting the subbed support to dry.

12. A process for the production of an electrically conducting copper plated silver image comprising immersing an exposed silver halide photographic emulsion on a support for 30-90 seconds in a monobath comprising a silver halide developer selected from the class consisting of 5- 30 g. per liter hydroxylamine hydrochloride and a mixture of 0.5-5 g. per liter of 1-phenyl-3-py-razolidone, and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmerca-pto) acetic acid, thiodiglycolic acid, and B,,6'-di-thiasuberic acid, transferring the conducting silver image to a subbed support which has been nucleated by bathing in a solution of a salt chosen from the class consisting of gold salts and stannous salts, blotted and dried, the transfer being eifected by placing the support emulsion side down on the subbed support immediately following removal from the monobath and applying pressure to the reverse side of the support, stripping the emulsion from the support and plating copper on the conducting silver layer.

13. A process for the production of an electrically con.- ducting silver image and its use as a xeroprinting plate comprising immersing an exposed silver halide photographic emulsion on a support for 30-90 seconds in a monobath comprising a silver halide developer selected from the class consisting of 5-30 g. per liter hydroxylamine hydrochloride and a mixture of 0.5-5 g. per liter of l-phenyl-B-pyrazolidone, and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing ,6 agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and 3,;3-dithiasuberic acid-transferring the conducting silver image to Y a subbed support which has been nucleated by bathing in a solution of a salt chosenfrom the class consisting of gold salts and stannous salts,.blotte;d.and dried, the transfer being effected by placing the support emulsion side .down on the subbed supportimmediately following removal from the monobath and applying pressure to the reverse side of the support, stripping the emulsion from the support and permitting the subbed support to dry,

placing a negative charge on the subbed support which carried the electrically conducting silver image using a corona discharge method, dusting the surface of the subbed support with positively charged particles, contacting the dusted surface with a sheet of receiving paper, negatively charging the sheet of paper causing the positive particles to adhere to the surface of the paper and heating the receiving paper containing the particles in order to 20 cause the particles to adhere to the surface of the paper.

14. A process for the production of an electrically conducting silver layer comprising immersing an exposed silver chloride photographic emulsion on a film support in a monobath for 30-90 seconds comprising 5-30 g. per liter hydroxylamine hydrochqloride and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and B,/3'-dithiasuberic acid.

15. A process for the production of an electrically con ducting silver layer comprising immersing an exposed silver halide photographic emulsion on a support in a monobath for 30-90 seconds comprising 5-30 g. per liter silver complexing agent selected from the class consisting 'of (ethylmercapto) acetic acid,'thiodiglycolic acid, and

3,B-dithiasuberic acid, transferring the conducting silver image to a subbed support which has been nucleated by bathing in a solution of a salt chosen from the class consisting of gold salts and stannous salts, blotted and dried, the transfer being effected by placing the support emulsion side down on the subbed support immediately following removal from the monobath and applying pressure to the back side of the support, stripping the emulsion from the support and permitting the subbed support to dry.

16. A process for the production of an electrically conducting copper plated silver layer comprising immersing an exposed silver halide photographic emulsion on a support in a monobath for 30-90seconds comprising 5-30 g. per liter hydroxylamine hydrochloride and 5-100 g. per liter of a. silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and B,fl'-dithiasuberic acid, transferring the conducting silver image to a subbed support which has been nucleated by bathing in a solution of a salt chosen from the class consisting of gold salts and stannous salts, blotted and dried, the transfer being effected by placing the support emulsion side down on the subbed support immediately following removal from the monobath and applying pressure to the back side of the support, stripping the emulsion from the support and plating copper on the conducting silver layer.

17. A process for the production of an electrically conducting silver layer and its use as a xeroprinting plate comprising immersing an exposed silver halide photogrphic emulsion on a support in a monobath for 30-90 seconds comprising 5-30 g. per liter hydroxylamine hydrochloride and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and B,r3'-dithiasuberic acid, transferring the conducting silver image to a subbed support which has been nucleated by bathing in a solution of a salt chosen from the class consisting of gold salts and stannous salts, blotted and dried, the transfer being effected by placing the support emulsion side down on the subbed support immediately following removal from the 7 monobath and applying pressure to the back side of the support, stripping the emulsion from the support and permitting the subbed support to dry, placing a negative charge on the subbed support which carries the electrical- -ly conducting silver image using a corona discharge method, dusting the surface of the subbed support with positively charged particles, contacting the dusted surface with a sheet of receiving paper, negatively charging the sheet of paper causing the positive particles to adhere to the surface of the upper and heating the paper con taining the particles in order to cause the particles to adhere to the surface of the paper.

18. A process for the production of an electrically conducting silver layer comprising immersing an exposed silver chloride photographic emulsion on a support in a monobath for 30-90 seconds comprising a mixture of 0.5- g. per liter l-phenyl-3-pyrazolidone and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and 18,]8'-dithiasuberic acid.

19. A process for the production of an electrically con ducting silver layer comprising immersing an exposed silver halide photographic emulsion on a support in a monobath for 30-90 seconds comprising a mixture of 0.5-5 g. per liter l-phenyl-S-pyrazolidone and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, transferring the conducting silver image to a subbed support which has been nucleated by bathing in a solution of a salt chosen from the class consisting of gold salts and stannous salts, blotted and dried, the transfer being effected by placing the support emulsion side down on the subbed support immediately following removal from the monobath and applying pressure to the back side of the support, stripping the emulsion from the support and permitting the subbed support to dry.

20. A process for the production of an electrically conducting copper plated silver laycr comprising immersing an exposed silver halide photographic emulsion on a support in a monobath for 30-90 seconds comprising a. mixture of 0.5-5 g. per liter 1-phenyl-3-pyrazolidone and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylmercapto) acetic acid, thiodiglycolic acid, and fi,fi'-dithiasuberic acid, transferring the conducting silver image to a subbed support which has been nucleated by bathing in a solution of a salt chosen from the class consisting of gold salts and stannous salts, blotted and dried, the transfer being efiected by placing the support emulsion side 'down on the subbed support immediately following removal from the monobath and applying pressure to the back side of the support, stripping the emulsion from the support and plating copper on the conducting silver layer.

21. A process for the production of an electrically conducting silver layer and its use as a xeroprinting plate comprising immersing an exposed silver halide photographic emulsion on a support in a monobath for 30-90 seconds comprising a mixture of 0.5-5 g. per liter 1- phenyl-3-pyrazolidone and 5-30 g. per liter hydroquinone and 5-100 g. per liter of a silver complexing agent selected from the class consisting of (ethylniercapto) acetic acid, thiodiglycolic acid, and 6,fl-dithiasuberic acid, trans ferring the conducting silver imageto 21 subbed support which has been nucleated by bathing in a solution of a salt chosen from the class onsisting of gold salts and stannous salts, blotted and dried, the transfer being eifected by placing the support emulsion side down on the subbed support immediately following removal from the monobath and applying pressure to the back side of the support, stripping the emulsion from the support and permitting the subbed support to dry, placing a negative charge on the subbed support which carries the electrically conducting silver image using a corona discharge method, dusting the surface of the subbed support with positively charged particles, contacting the dusted suriiace with a sheet of receiving paper, negatively charging the sheet of paper causing the positive particles to adhere to the surface of the paper and heating the paper containing the particles in order to cause the particles to adhere to the surface of the paper.

References Cited in the file of this patent UNITED STATES PATENTS 1,673,522 Matthies June 12, 1928 2,573,881 Walkup Nov. 6, 1951 2,600,343 Tuttle June 10, 1952 2,615,828 Haefele Oct. 28, 1952 2,686,717 Land Aug. 17, 1954 2,719,815 Sanders Oct. 4, 1955 2,725,298 Yutzy et al Nov. 29, 1955 FOREIGN PATENTS 761,368 Great Britain Nov. 14, 1956 531,409 Canada Oct. 9, 1956 OTHER REFERENCES Chemical Abstracts, 42, 8956b. Chemical Abstracts, 47, 7247i. 

12. A PROCESS FOR THE PRODUCTION OF AN ELECTRICALLY CONDUCTING COPPER PLATED SILVER IMAGE COPRISING IMMERSING AN EXPOSED SILVER HALIDE PHOTOGRAPHIC EMULSION ON A SUPPORT FOR 30-90 SECONDS IN A MONOBATH COMPRISING A SILVER HALIDE DEVELOPER SELECTED FROM THE CLASS CONSISTING OF 530 G. PER LITER HYDROXYLAMINE HYDROCHLORIDE AND A MIXTURE OF 0.5-5G. PER LITER OF 1-PHENYL-3-PYROZOLIDONE, AND 5-30 G. PER LITER HYDROQUINONE AND 5-100 G. PER LITER OF A SILVER COMPLEXING AGENT SELECTED FROM THE CLASS CONSISTING OF (ETHYLKMERCAPTO) ACETIC ACID, THIODIGLYCOLIC ACID, AND B,B''-DITHIASUBERIC ACID, TRANSFERRING THE CONDUCTING SILVER IMAGE TO A SUBBED SUPPORT WHICH HAS BEEN NUCLEATED BY BATHING IN A SOLUTION OF A SALT CHOSEN FROM THE CLASS CONSISTING OF GOLD SALTS AND STANNOUS SALTS, BLOTTED AND DRIED, THE TRANSFER BEING EFFECTED BY PLACING THE SUPPORT EMULSION SIDE DOWN ON THE SUBBED SUPPORT IMMEDIATELY FOLLOWING REMOVAL FROM THE MONOBATH AND APPLYING PRESSURE TO THE REVERSE SIDE OF THE SUPPORAT, STRIPPING THE EMULSION FROM THE SUPPORT AND PLATING COPPER ON THE CONDUCTING SILVER LAYER. 